Discontinued Operations and Assets Held for Sale (Table Illustration of Discontinued Operations in Income Statement) (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Discontinued Operations
Revenues	$ 1,341	$ 11,385	$ 7,506	$ 38,276
Operating expenses	(640)	(4,675)	(3,751)	(15,226)
Depreciation and amortization on discontinued operations	(426)	(3,426)	(1,678)	(10,877)
Operating income	275	3,284	2,077	12,173
Interest expense	(311)	(2,909)	(2,107)	(9,880)
Income (loss) before gain on sales	(36)	375	(30)	2,293
Gain on sale of depreciable properties	2,088	11,527	16,405	24,383
Income from discontinued operations	$ 2,052	$ 11,902	$ 16,375	$ 26,676